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GerR Commitment to sporulation and engulfment (Stages II - III)

GerR during commitment to sporulation

Originally described as YlbO, GerR is a DNA binding protein with regulatory properties ¹¹³. Transcription of its gene is under dual control of σ^E-containing RNA polymerase and SpoIIID ⁹⁶. Its function in the mother cell is similar to that of RsfA in the forespore, indicated also by the 52% protein similarity¹⁰⁸. Transcriptional profiling experiments identified 14 σ^E-dependent genes to be co-dependent on GerR ⁹⁵. Similar to SpoIIID, GerR mostly has a negative effect on gene transcription, which in some cases reaches its maximum by the combined actions of GerR and SpoIIID.

Next to its repressing activity on a small subset of σ^E-dependent genes, GerR was found to positively and negatively regulate a few (mainly coat protein encoding) genes that are identified within the σ^K regulon, alone or in conjunction with GerE (also see the ENGULFMENT state) ^{96, 113}. Even though this extended activity of GerR during the sporulation process was shown to be direct on some genes like spoVIF, cotB and cotU, other effects have been postulated to be indirect. This indirect regulation is likely achieved through the posttranslational effect that the GerR-mediated action has on GerE in the mother cell during later stages of sporulation ⁹⁶.